JP3611591B2 - Portable electronic device with depth gauge - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a portable electronic device having a water depth measuring function and a function of detecting water or seawater when touched, and relates to reduction of power consumption.
[0002]
[Prior art]
Conventionally, an external terminal that is insulated from the outer case is provided, and the external terminal is connected to a potential different from that of the outer case by resistance. When this portion gets wet with water, the electrical resistance between the outer case and the outer terminal decreases. For example, Japanese Utility Model Laid-Open No. 60-183895 has proposed that a water detection means utilizing this fact is used and a water pressure sensor is automatically driven to start water depth measurement.
[0003]
[Problems to be solved by the invention]
However, in the prior art, while the outer case and the external terminal are wet with water, current always flows from the outer case through the water, the external terminal, and the resistance to increase the power consumption. For this reason, the consumption of the battery is accelerated, and the battery is frequently replaced, which impairs convenience as a portable electronic device.
[0004]
The objective of this invention is providing the portable electronic device with a depth gauge which has the water detection means which solves the said subject and has little power consumption.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the configuration of the present invention includes a water pressure sensor that detects a water pressure value and generates a water pressure signal, a driving means that drives the water pressure sensor, a sampling process of the water pressure signal from the water pressure sensor, and a water depth signal. Water depth data processing means for converting into information, display means for displaying the water depth information, water detection means for detecting that water or seawater is in contact, and an external to which the water detection means is connected And the water detecting means operates intermittently, and the external terminal is set to the same potential as the exterior case during non-operation.
[0006]
【Example】
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram of an embodiment of a portable electronic device with a depth gauge according to the present invention. 1 is a water pressure sensor, and 2 is a drive means. When a water detection signal from a terminal Q of a DFF 73 of the water detection means 7 described later is input to the terminal S, the water pressure sensor 1 is driven. The water pressure sensor 1 is driven by the driving means 2 to detect a water pressure value and generate a water pressure signal. Reference numeral 3 denotes water depth data processing means. When a water detection signal from the terminal Q of the DFF 73 of the water detection means 7 is input to the terminal S, the water pressure signal from the water pressure sensor 1 is sampled and converted into water depth information. Reference numeral 4 denotes display means for displaying water depth information from the water depth data processing means 3. Reference numeral 100 denotes an exterior case, which is connected to the voltage level VDD. Reference numeral 9 denotes an external terminal, which is electrically insulated from the outer case 100 and formed on the side surface of the outer case 100. Reference numeral 5 denotes a clock generating means which normally outputs a VSS level and intermittently generates a VDD level sample signal Ps with a pulse width Tp at a period Ts. Reference numeral 7 denotes water detection means, which is composed of a Pch MOS transistor (hereinafter abbreviated as PMOS) 71, an Nch MOS transistor (hereinafter abbreviated as NMOS) 72, a D-type flip-flop (hereinafter abbreviated as DFF) 73, and an Rd 74 as a pull-down resistor. . The PMOS 71 has a source connected to the VDD level, a drain connected to the external terminal 9, and a gate connected to the clock generating means 5. The NMOS 72 has a source connected to the VSS level, a drain connected to the external terminal 9 via the Rd 74, and a gate connected to the clock generating means 5. The DFF 73 has a terminal D connected to the external terminal 9 and a terminal φ connected to the clock generating means 5. The DFF 73 reads the voltage level of the external terminal 9 in synchronization with the fall of the sample signal Ps, and the read voltage level becomes the VDD level. A water detection signal is generated from the terminal Q when it is closer to the VDD level than VH, which is an intermediate voltage level of the VSS level, and no water detection signal is generated otherwise.
[0007]
FIG. 2 is a top view of an embodiment of a portable electronic device with a depth gauge according to the present invention. An insulating member 200 ensures electrical insulation between the external terminal 9 provided on the left side surface of the outer case 100 and the outer case 100. The water pressure sensor 1 is provided on the right side surface of the outer case 100, and the display unit 4 is provided on the upper surface of the outer case 100.
[0008]
FIG. 3 is a cross-sectional view of the vicinity of the external terminal of FIG. The external terminal 9 is fixed to the exterior case 100 in the lateral hole formed in the exterior case 100 while ensuring electrical insulation by the insulating member 200, and the waterproof property is also secured.
[0009]
The operation of the portable electronic device with a depth gauge according to the present invention having the above-described configuration will be described with reference to FIGS.
FIG. 4 is a time chart for explaining the operation. As shown in FIG. 4A, the clock generating means 5 normally outputs a voltage of VSS level, and outputs a sample clock Ps having a voltage of VDD level and a pulse width Tp every cycle Ts. When the output of the clock generating means 5 is at the VSS level, the PMOS 71 is turned on because the gate of the PMOS 71 is at the VSS level, and the NMOS 72 is turned off because the gate of the NMOS 72 is also at the VSS level. Therefore, the external terminal 9 is at the VDD level, that is, the same voltage level as the exterior case 100. Next, when the sample signal Ps is output from the clock generating means 5, the gate of the PMOS 71 is at the VDD level, so the PMOS 71 is turned off, and the gate of the NMOS 72 is also at the VDD level, so the NMOS 72 is turned on. Therefore, the external terminal 9 is pulled down to the VSS level via Rd74. That is, the external terminal 9 is normally at the same voltage level VDD as that of the outer case 100, and is pulled down by Rd74 only when the sample signal Ps is generated at the cycle Ts.
[0010]
When the external terminal 9 before the dive is started and the exterior case 100 are dry, when the sample signal Ps is generated, the external terminal 9 is electrically insulated from the exterior case 100 as shown in FIG. Therefore, the voltage is pulled down to the VSS level by the Rd 74 and the NMOS 72 and becomes a voltage closer to the VSS level than the voltage level VH. The DFF 73 reads the voltage level of the external terminal 9 at the falling edge of the sample signal Ps, but does not generate a water detection signal from the terminal Q because it is closer to VSS than the voltage level of VH. Therefore, neither the drive means 2 nor the water depth data processing means 3 is operating.
[0011]
Next, it is assumed that diving is started and the external terminal 9 and the outer case 100 are brought into conduction at a resistance value lower than the resistance value of Rd74 by contacting the water. At this time, when the sample signal Ps is output, as shown in FIG. 4C, the external terminal 9 is pulled down to the VSS level by the Rd 74 and the NMOS 72, but is electrically connected to the exterior case 100 at the VDD level as described above. Therefore, the voltage level of the external terminal 9 is closer to the VDD level than the voltage level of VH. The DFF 73 reads the voltage level of the external terminal 9 at the falling edge of the sample signal Ps, and generates a water detection signal from the terminal Q because it is closer to the VDD level than the voltage level of VH. Accordingly, both the driving means 2 and the water depth data processing means 3 start to operate. The water pressure sensor 1 driven by the drive circuit 2 outputs a water pressure signal to the water depth data processing means 3, and the water depth data processing means 3 samples the water pressure signal, converts it into water depth information, and displays it on the display means 4.
[0012]
When the diving is finished, there is no water conducted between the external terminal 9 and the outer case 100, and the external terminal 9 and the outer case 100 are electrically insulated again, so that the state before the diving is started. . No water detection signal is output from the water detection means 7, and the drive means 2 and the water depth data processing circuit stop operating.
[0013]
【The invention's effect】
Since the external terminal is usually during this time because it is the outer casing and the same potential does not flow even current wet with water, the current flow is when the sample signal Ps width Tp at the period Ts occurs, the external terminal The current flowing between the outer case and the outer case can be suppressed to the conventional Tp / Ts. By setting the width Tp to be sufficiently small with respect to the period Ts, it is possible to realize water detection means with low power consumption that can suppress this current to a level that can be almost ignored. Therefore, it is possible to provide a more convenient portable electronic device with a depth gauge by suppressing battery consumption and extending the battery life and reducing the frequency of battery replacement.
[Brief description of the drawings]
FIG. 1 is a block diagram of an embodiment of a portable electronic device with a depth gauge according to the present invention.
FIG. 2 is a top view of an embodiment of a portable electronic device with a depth gauge according to the present invention.
3 is a cross-sectional view of the vicinity of an external terminal in FIG.
FIG. 4 is a time chart for explaining the operation of an embodiment of the portable electronic device with a depth gauge according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Water pressure sensor 2 Drive means 3 Water depth data processing means 4 Display means 5 Clock generation means 7 Water detection means 9 External terminal 100 Exterior case

Claims (1)

A water pressure sensor that detects a water pressure value and generates a water pressure signal, a drive unit that drives the water pressure sensor, a water depth data processing unit that samples the water pressure signal from the water pressure sensor and converts it into water depth information, and the water depth information Display means for displaying, water detection means for detecting that water or seawater is in contact with two transistors, an external terminal to which the water detection means is connected, and the external terminal It has an exterior case fixed by an insulating member and a clock generation means for generating a sample signal. When one of the transistors is turned on by the sample signal, the other transistor is turned off, The external terminal is set to the same potential as the outer case, and when the sample signal is generated, the external terminal is connected to the outer case. Portable electronic device with depth meter and detects that the water or seawater in contact with the voltage level of the external terminals by pulling down on becomes potential.

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